Page level key-based memory protection

ABSTRACT

Embodiments of the present invention provide an approach for memory protection at a level of granularity above a “page” level (e.g., enhancing the protection provided by a memory key-based system). The approach further provides such a level of protection at a process or task level by associating the physical page key with a virtual key that corresponds to a particular process/task. When access to the data is requested for a particular process or task, it is determined if a protection bit for the data is set, and if the physical page keys and/or virtual keys submitted pursuant to the request match that previously stored for the data and process/task. If so, access to the data is allowed for the particular process/task.

TECHNICAL FIELD

Embodiments of the present invention relate to data security management.Specifically, embodiments of the present invention relate to a key-basedapproach for protecting data.

BACKGROUND OF THE INVENTION

Statutory provisions today may include aspects that affect manyindustries with concerns such as personal data security, banking datasecurity, medical data protection, etc. As these provisions becomeincreasingly complex, it has become more difficult for a serviceprovider to avoid access to unauthorized data and still provide theircontracted services. One cause of such issues has to do with dataresiding in main storage and the ability of a processor to load thatdata for use by an application that is genuinely entitled to access thatdata at that moment in time versus an application that has not beenentitled to access that information.

Another complication has to do with collecting data for use as a serviceprovider and the ability of that service provider to perform servicework needed to solve problems on that computer system. Specifically,when variables go out of scope in a system, or are de-allocated inmemory allocation systems, it is possible for that memory to remainvisible to other parts of the computer system. This could potentiallyallow harmful code execution to read that memory and obtain theinformation that was not cleared by a software initialization or thelike.

SUMMARY

Embodiments of the present invention provide an approach for memoryprotection at a level of granularity above a “page” level (e.g.,enhancing the protection provided by a memory key-based system). Theapproach further provides such a level of protection at a process ortask level by associating the physical page key with a virtual key thatcorresponds to a particular process/task. When access to the data isrequested for a particular process or task, it is determined if aprotection bit for the data is set and if the physical page keys and/orvirtual keys submitted pursuant to the request match that previouslystored for the data and process/task. If so, access to the data isallowed for the particular process/task.

A first aspect of the present invention provides a computer-implementedmethod for managing data security, comprising: identifying a set ofpages of data in computer storage; generating a physical key for eachpage of the set of pages, the physical key being stored in at least onetable; generating a virtual key based on each physical key, the virtualkey identifying at least one process authorized to use the data, and thevirtual key being stored in at least one register; protecting each pageof the set of pages with a respective physical key and correspondingvirtual key; and setting a data protection bit to a particular settingto indicate a protective status of the set of pages of data.

A second aspect of the present invention provides a system for managingdata security, comprising: a bus; a processor coupled to the bus; and amemory medium coupled to the bus, the memory medium comprisinginstructions to: identify a set of pages of data in computer storage;generate a physical key for each page of the set of pages, the physicalkey being stored in at least one table; generate a virtual key based oneach physical key, the virtual key identifying at least one processauthorized to use the data, and the virtual key being stored in at leastone register; protect each page of the set of pages with a respectivephysical key and corresponding virtual key; and set a data protectionbit to a particular setting to indicate a protective status of the setof pages of data.

A third aspect of the present invention provides a computer programproduct for managing data security, the computer program productcomprising a computer readable storage media, and program instructionsstored on the computer readable storage media, to: identify a set ofpages of data in computer storage; generate a physical key for each pageof the set of pages, the physical key being stored in at least onetable; generate a virtual key based on each physical key, the virtualkey identifying at least one process authorized to use the data, and thevirtual key being stored in at least one register; protect each page ofthe set of pages with a respective physical key and correspondingvirtual key; and set a data protection bit to a particular setting toindicate a protective status of the set of pages of data.

A fourth aspect of the present invention provides a method for deployinga system for managing data security, comprising: providing a computerinfrastructure being operable to: identify a set of pages of data incomputer storage; generate a physical key for each page of the set ofpages, the physical key being stored in at least one table; generate avirtual key based on each physical key, the virtual key identifying atleast one process authorized to use the data, and the virtual key beingstored in at least one register; protect each page of the set of pageswith a respective physical key and corresponding virtual key; and set adata protection bit to a particular setting to indicate a protectivestatus of the set of pages of data.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings in which:

FIG. 1 depicts a computing node according to an embodiment of thepresent invention.

FIG. 2 depicts a system diagram according to an embodiment of thepresent invention.

FIG. 3 depicts a data protection bit schema according to an embodimentof the present invention.

FIG. 4 depicts a physical page table in which physical page keys may bestored according to an embodiment of the present invention.

FIG. 5 depicts a table entry associated with other components accordingto an embodiment of the present invention.

FIG. 6 depicts the association of protected memory/data with a dataprotection bit according to an embodiment of the present invention.

FIG. 7 depicts a process flow diagram according to an embodiment of thepresent invention.

FIG. 8 depicts a process flow diagram according to an embodiment of thepresent invention.

FIG. 9 depicts a process flow diagram according to an embodiment of thepresent invention.

FIG. 10 depicts a process flow diagram according to an embodiment of thepresent invention.

FIG. 11 depicts a process flow diagram according to an embodiment of thepresent invention.

FIG. 12 depicts a method flow diagram according to an embodiment of thepresent invention.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention, and therefore should not be considered aslimiting the scope of the invention. In the drawings, like numberingrepresents like elements.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments will now be described more fully herein withreference to the accompanying drawings, in which exemplary embodimentsare shown. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these exemplary embodiments areprovided so that this disclosure will be thorough and complete and willfully convey the scope of this disclosure to those skilled in the art.In the description, details of well-known features and techniques may beomitted to avoid unnecessarily obscuring the presented embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of this disclosure.As used herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Furthermore, the use of the terms “a”, “an”, etc., do notdenote a limitation of quantity, but rather denote the presence of atleast one of the referenced items. The word “set” is intended to mean aquantity of at least one. It will be further understood that the terms“comprises” and/or “comprising”, or “includes” and/or “including”, whenused in this specification, specify the presence of stated features,regions, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Embodiments of the present invention provide an approach for memoryprotection at a level of granularity above a “page” level (e.g.,enhancing the protection provided by a memory key-based system). Theapproach further provides such a level of protection at a process ortask level by associating the physical page key with a virtual key thatcorresponds to a particular process/task. When access to the data isrequested for a particular process or task, it is determined if aprotection bit for the data is set, and if the physical page keys and/orvirtual keys submitted pursuant to the request match that previouslystored for the data and process/task. If so, access to the data isallowed for the particular process/task.

Performance is greatly enhanced over several known securityalternatives. Larger quantities of memory may be protected, while eachgranularity of protection is still controllable. Increasedserviceability is provided for data collection processes through the useof memory access exception handlers and replacement text for thosegranularities of memory whose data protection bits are set. This allowscompanies who cannot send data to a service provider for any of variousreasons to be able to collect data needed to solve system problems in asensitive environment. The requirement for data security is driven backto the application programmer with operating system, which enablesfurther support for restrictive Euro-laws with respect to physicallocation of data stored and location of person accessing data, as wellas authentication of user accessing data.

An aspect of the present invention provides for a system of memoryprotection at a level of granularity above the page level (enhancing theprotection provided by a memory keys system). As further describedabove, a similar level of protection is provided hereunder at theprocess or task level by associating a key with a logical page ofstorage to enable page level granularity by comparing that keyassociated with the page of storage to the protection bits. If a dataprotection bit is set and a key for the page of data mismatches that ofthe current processor or thread, a protection exception occurs. Suchfunctionality is enabled by (among other things):

Defining a data protection bit to go along with some granular level ofmemory access (such as a word, a cache line, etc). The bit would bestored either: (a) an EMP page, or (b) along with memory by adding anextra bit to coexist with some granular level of memory.

Defining a physical page key to be stored for each page in the physicalpage table of a system. In one embodiment, this physical page key listcould be stored in a separate table addressable by the kernel or systemstate of the operating system only. An embodiment of the physical pagekey could create it as a compressed key from which other virtual pagekeys could be derived for use by processes. Another embodiment could(with a lower level of security) store the physical page key and providethat key directly to the processes in lieu of a derived virtual pagekey.

Defining a virtual page key to go along with the process or task image.This virtual page key could be saved and restored as a part ofcall/return methods such as stack frames. The virtual page key couldalso be defined as a part of a unique activation.

Defining a central processing unit (CPU) register to store the currentcontext's virtual page key during runtime (such as used for memory keypage protection).

Defining a software mechanism to create a physical page key from whichprocess-derived keys may be defined. A physical page key would becreated and associated with an owning process, and possibly at anactivation group level where necessary.

Defining a software mechanism to securely derive a process key from aphysical page key through the use of a reference to the physical pagekey. No user level process would ever be able to read a physical pagekey directly. At process creation, an operating system could requestcreation of a physical page key followed by derivation of a virtual pagekey for that activation or process. A main process could then use afunction to duplicate the reference to the physical page key. In oneembodiment, the physical page key reference may only be valid for theprocess or thread identifier associated with the context in question. Inanother embodiment, it may be possible to create a virtual page key thatwas usable process wide. In yet another embodiment, it may be possibleto create separate thread level virtual page keys, and even a separateactivation for a thread such that a thread's storage could be isolatedfrom other threads in the same process context.

Defining a hardware mechanism to store a protection bit along with thedata of user registers. This would increase the size of the userregister itself by one bit.

Defining an architecture to maintain and control the protection state ofdata: (1) loaded into the CPU from components (e.g., memory, anotherregister, an I/O device, arithmetic operation (including controls withina floating point co-processing subsystem), immediate data, etc.), and/or(2) stored in/from the CPU (e.g., to memory, and I/O device, etc.)

Defining an I/O architecture to enable either DMA or MMI/O, as well asother I/O mechanisms to support providing a memory protection mask forthe memory in which an I/O read operation is to be performed; or toallow the I/O write operation to complete.

Along these lines, the following terminology may be utilized hereunder:

Physical Page Key—A key created by an operating system to providephysical page level data protection.

Virtual Page Key—A key derived from a physical page key. This key isintended for process contexts to use during memory access operations.

Data Protection Bit—A bit to be associated with a granularity of memory(such as a word or memory cache line, but intended to be smaller than aphysical page of memory). An “on” state indicates the data stored inthis granular memory location is protected from access by any process orthread context not having the correct virtual page key that matches oris derived from the physical page key. With the data protection bit onand a “mis-compare” of the virtual page key signature against thephysical page key signature, a data access violation exception can besignaled. In one embodiment, a memory access violation may includeadditional exception information to describe the reason for the memoryaccess violation as being an attempt to operate on memory with anincorrect virtual page key.

Referring now to FIG. 1, a schematic of an example of a computing nodeis shown. Computing node 10 is only one example of a suitable computingnode and is not intended to suggest any limitation as to the scope ofuse or functionality of embodiments of the invention described herein.Regardless, computing node 10 is capable of being implemented and/orperforming any of the functionality set forth hereinabove.

In computing node 10, there is a computer system/server 12, which isoperational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 12 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, hand-held or laptop devices, mobile devices,global positioning systems (GPS), GPS-enable devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed computing environments that includeany of the above systems or devices, and the like.

Computer system/server 12 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon, that perform particular tasks or implement particular abstract datatypes. Computer system/server 12 may be practiced in distributedcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed computing environment, program modules may be located inboth local and remote computer system storage media including memorystorage devices.

As shown in FIG. 1, computer system/server 12 in computing node 10 isshown in the form of a general-purpose computing device. The componentsof computer system/server 12 may include, but are not limited to, one ormore processors or processing units 16, a system memory 28, and a bus 18that couples various system components including system memory 28 toprocessor 16.

Bus 18 represents one or more of any of several types of bus structures,including a memory bus or memory controller, a peripheral bus, anaccelerated graphics port, and a processor or local bus using any of avariety of bus architectures. By way of example, and not limitation,such architectures include Industry Standard Architecture (ISA) bus,Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, VideoElectronics Standards Association (VESA) local bus, and PeripheralComponent Interconnects (PCI) bus.

Computer system/server 12 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 12, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 28 can include computer system readable media in the formof volatile memory, such as random access memory (RAM) 30 and/or cachememory 32. Computer system/server 12 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 34 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM, or other optical media can be provided.In such instances, each can be connected to bus 18 by one or more datamedia interfaces. As will be further depicted and described below,memory 28 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

The embodiments of the invention may be implemented as a computerreadable signal medium, which may include a propagated data signal withcomputer readable program code embodied therein (e.g., in baseband or aspart of a carrier wave). Such a propagated signal may take any of avariety of forms including, but not limited to, electro-magnetic,optical, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that can communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium including, but not limited to, wireless,wireline, optical fiber cable, radio-frequency (RF), etc., or anysuitable combination of the foregoing.

Data security program/utility 40, having a set (at least one) of programmodules 42, may be stored in memory 28 by way of example, and notlimitation. Memory 28 may also have an operating system, one or moreapplication programs, other program modules, and program data. Ingeneral, Data security 40 performs the function of the present inventionas described herein. Each of the operating system, one or moreapplication programs, other program modules, and program data or somecombination thereof, may include an implementation of a networkingenvironment. Program modules 42 generally carry out the functions and/ormethodologies of embodiments of the invention as described herein.

Computer system/server 12 may also communicate with one or more externaldevices 14 such as a keyboard, a pointing device, a display 24, etc.;one or more devices that enable a consumer to interact with computersystem/server 12; and/or any devices (e.g., network card, modem, etc.)that enable computer system/server 12 to communicate with one or moreother computing devices. Such communication can occur via I/O interfaces22. Still yet, computer system/server 12 can communicate with one ormore networks such as a local area network (LAN), a general wide areanetwork (WAN), and/or a public network (e.g., the Internet) via networkadapter 20. As depicted, network adapter 20 communicates with the othercomponents of computer system/server 12 via bus 18. It should beunderstood that although not shown, other hardware and/or softwarecomponents could be used in conjunction with computer system/server 12.Examples include, but are not limited to: microcode, device drivers,redundant processing units, external disk drive arrays, RAID systems,tape drives, and data archival storage systems, etc.

Referring now to FIG. 2, a system diagram describing the functionalitydiscussed herein according to an embodiment of the present invention isshown. It is understood that the teachings recited herein may bepracticed within any type of networked computing environment (e.g., acloud computing environment). A computer system/server 12, which can beimplemented as either a stand-alone computer system, or as a networkedcomputer system is shown in FIG. 2. In the event the teachings recitedherein are practiced in a networked computing environment, each clientneed not have a data security engine (engine 50). Rather, engine 50could be loaded on a server (e.g., payment processing server) orserver-capable device that communicates (e.g., wirelessly) with theclients to provide data security functionality hereunder. Regardless, asdepicted, engine 50 is shown within computer system/server 12. Ingeneral, engine 50 can be implemented as program/utility 40 on computersystem 12 of FIG. 1 and can enable the functions recited herein. Asfurther shown, engine 50 (in one embodiment) comprises a rules and/orcomputational engine that processes a set (at least one) of rules/logic52 and/or provides data security functionality hereunder.

Along these lines, engine 50 may perform multiple functions similar to ageneral-purpose computer. Specifically, among other functions, engine 50may (among other things): identify a set of pages of data 56A-N incomputer storage 60; generate a physical key 62 for each page of the setof pages 56A-N, the physical key 62 being stored in at least one table66; generate a virtual key 64 based on each physical key 62, the virtualkey 64 identifying at least one process authorized to use the data, andthe virtual key 64 being stored in at least one register 68; protecteach page of the set of pages 56A-N with a respective physical key 62and corresponding virtual key 64; set a data protection bit 58A-N to aparticular setting (e.g., “protected”) to indicate a protective statusof the set of pages of data 56A-N; receive a request 54 to access thedata (in pages 56A-N) for a particular process (the request havinginstructions and submitted keys such as a submitted physical key and/orvirtual key); determine if the data projection bit 58A-N (i.e.,associated with the page(s) of data sought to be accessed) is set to theparticular setting; identify, based on the at least one table 66 and theat least one register 68, at least one physical key 62 and at least onevirtual key 64 that corresponds to the data page(s) and the particularprocess; determine if the at least one physical key 62 and the at leastone virtual key 64 match a physical key and a virtual key associatedwith the request 54; make, based upon the determining, an authenticationdetermination for the requested access to the data; signal a dataprotection exception 70 if any one of the at least one physical key 62and at least one virtual key 64 mismatch the physical key and thevirtual key associated with request 54; clear a set of user registers(104A-N of FIG. 7) whose corresponding data protection bits (102A-N ofFIG. 7) are engaged in response to a virtual page key register 68 beingloaded in a system state; toggle (e.g., clear or set) the dataprojection bit (210A-N of FIG. 8) based upon an instruction; transferthe data projection bit (308A-N of FIG. 9) between a set of userregisters (306A-N of FIG. 9) during at least one of a load operation andan arithmetic operation; and/or set a data protection bits (404A-N ofFIG. 10) associated with a data processing result based on a dataprotection bit (404A-N of FIG. 10) associated with an operand (402A-N ofFIG. 10) of a machine instruction.

In describing these concepts in further detail, the followingdefinitions may be utilized:

Data Protection (DP) Bit:

As indicated above, a data protection bit is defined to be associatedwith some level of granularity of system memory. An example of this isshown in FIG. 3. As depicted, each physical page 82A-N in memory/storage80 may have a block protected memory/data 84A-N and an associated dataprotection (DP) bit 86A-N. Specifically, for effective systemperformance, each DP bit 86A-N should be associated with a block ofmemory 84A-N that can be bracketed by addresses that are on a power oftwo boundary, so that each segment of protected memory could be onebyte, two bytes, four bytes, etc., wide. An ideal performance boundarymay be that of one cache line in width for L3 or L2 cache associatedwith the processor.

In one embodiment, the DP bit would be stored as an array of bitsassociated with a physical page table 83 (an extended memory protectiontable (EMP)) having page table entries (PTEs) 85A-N as shown in FIG. 4.FIG. 5 shows further details of this embodiment in which a table entry85 is associated with a physical page number (PPN) 90, an allocation bit92, a DP bit array 94, and a physical page key (PPK) 96. Anotherembodiment could request the computing hardware to store the additionalbit as a physical part of each memory column (increasing a word size byone bit). An example of this is shown in FIG. 6. As depicted, each blockof protected memory 84A-N is associated/stored with its corresponding DPbit 86A-N. One advantage of storing the array as a part of the physicalpage table or as a part of an EMP table is that the size of theprotection could be varied through hardware and software configurationsin the processor.

The DP bit is used to indicate that the protected piece of memory (seeFIG. 3) is either access protected or not. Access protection means thatan attempt to load or store data to the protected piece of memoryrequires special handling by the system CPU. This special handlinginvolves comparison of the physical page key's signature before allowingthe operation.

Physical Page Key (PPK):

The physical page key is a unique number or key generated for comparisonpurposes for all protected memory ranges within a physical page ofmemory. Various embodiments could be used to provide this key, includingsimple random number generation, sequential number generation, or morecomplicated solutions such as a signed private key generation (i.e., asused in open secure sockets layer (SSL) and other encryption systems).However, an intermediate approach not intended for use in communicationwould seem more appropriate.

One objective of a key-based system is to allow two functions to bederived. The first function can produce a signature of the physical pagekey. The second function is one where an additional key can be producedwhose signature is the same as that of the physical page key (e.g., seevirtual page key below for details). Each generated physical page keywould need to be unique along with the signature of that page key. Aphysical page key does not need to be generated for each physical pageof memory. Instead, the physical page key would be created when a newactivation or process is created. Thus, the number of unique page keysdoes not need to equal the physical number of memory pages in thesystem. Because of the unique requirement of the physical page key andthe signature of that physical page key, it makes sense that a masterfunction and table be provided within the kernel of the operating systemto generate the key and track those keys and signatures.

In one embodiment, the physical page key and the signature of thatphysical page key could be the same. In another, a larger or morecomplex physical page key could exist whose signature is smaller, whilestill providing a unique signature for all values in use. The physicalpage key would be stored along with the physical page table or alongwith an extended memory protection table (see FIG. 5).

Virtual Page Key (VPK):

A virtual page key has one or more unique numbers which are used torefer to a physical page key for the purposes of memory storage. Thepurpose of a virtual page key is one that allows more than one processto be allowed to operate on a physical page of memory, thus providingsupport for memory protection in shared memory spaces. The virtual pagekey must have a function that can produce a signature that in oneembodiment refers to the physical page key or, in another, the signatureof the physical page key. The function to produce this could be softwareor a hardware implemented lookup function to simply load the signatureor key of the physical page key for comparison purposes.

CPU Virtual Page Key (VPK) Register:

This is a register that would need to be a part of the CPU to store thevirtual page key that is in use by the current context (such as aprocess, thread, or activation). In one embodiment, no user-statemethodology would exist to load this register into a user register or tostore it into memory. Instead, this register would need to be loadedwith a signature of the virtual page key during context switch in, orduring creation of a new process or activation.

Register Data Protection (DP) Bits:

Each user register within the CPU of the computer system would need tobe enhanced to provide storage for the data protection bit. This bitwould be passed along with user register operations. This bit would alsobe provided in floating point registers and arithmetic and logic units.

CPU Data Protection Operations:

The CPU of such a system may be enhanced to meet one or morerequirements. One constraint of such a system is that no mechanism mayexist to bypass data protection bits when they are set “on” while theCPU is in a user state. This may include the storage of the keycurrently stored in the CPU into virtual memory accessible by a userprocess. So, during an interrupt processing, etc, this data may bestored (with operating system (OS) support) in kernel memory space. Assuch, the approach described herein provides (among other things) one ormore of the functions set forth below:

One function provided, as described in FIG. 7, is the ability to clearuser registers 104A-N whose data protection (DP) bit 102A-N is set “on”when the CPU's virtual page key register 108 is loaded to a systemstate. In this instance, the DP bits 102A-N would also be cleared. Forthis operation, it is determined in step P1 whether instruction decodinga step of the CPU has determined that an instruction is a load to thevirtual page key register 108. If not, the process may continue. If so:(1) A zero data 106 is latched to a register data bus of the CPU; (2)the DP bit 102A-N of each register is read and used to drive arespective AND gate 100A-N whose other operand is a store “strobe” ofthe same register; (3) as a result of the store being raised to thoseregisters 104A-N whose DP bit 102A-N is “on”, the zero data that is onthe data bus is latched into the register. Next, a phase decode isperformed in step P2 on an instruction 110 (e.g., register or operandinstruction), and it is determined if the CPU state is set equal to“system” in step P3. If not, a data protection exception may betriggered in step P4. If so, the system performs the next step ofselecting user register from the instruction, and loading thecorresponding data onto the data bus. Then, a latch operation may beperformed on the system virtual page key register 108. In oneembodiment, the virtual page key register 108 may become zero if the DPbit of the selected register is set. In another embodiment, the virtualpage key register 108 could be loaded first. However, loading thevirtual page key register 108 first may result in a security exposure ifany other data storage exception is taken and not handled properlybefore the registers are cleared. In another embodiment, virtual pagekey register 108 may require a looped load from multiple registers inorder to fully load the register. In yet another embodiment, virtualpage key register 108 may be loaded from a memory operand, although somesecurity exposure exists with this methodology requiring the operatingsystem to be in a state such that user state programs could not havevisibility to memory containing the virtual page key values.

Another function provided is the ability to clear or set the DP bit in aregister with a load immediate data operation as shown in FIG. 8. Asdepicted, it is determined in step R1 whether a user register load isimmediate. If not, the process may continue. If so, a register decodeoperation is performed in step R2 based on an instruction 202 that isfirst subjected to a phase decode operation in step R3. As shown,instruction 202 is accompanied in string 200 by DP bit 204 andcorresponding data 206. Instructions that load a register 208A-N withimmediate data would need to set aside a bit in the instruction toindicate whether this is a load with data protection or a load withoutdata protection. That bit would be used to set or reset the DP bit210A-N of the appropriate CPU register during a data latch cycle of aninstruction execution phase.

Another function provided hereunder is the ability to transfer a DP bit308A-N between registers 306A-N during load or arithmetic operations asshown in FIG. 9. As shown, it is determined in step S1 whether a userregister load is immediate. If not, the process may continue. If so, aregister decode operation is performed in step S2 based on aninstruction 300 (e.g., having source register identifier 302 and adestination register identifier 304 that is first subjected to a phasedecode operation in step S3. In one embodiment, an instruction may existas a latch into a temporary register 310 (e.g., intermediate result)with the DP bit 312 to be transferred. In another embodiment, a loadregister may exist as arithmetic “add” of zero without side effectsthrough the arithmetic logic unit (ALU) of the CPU. One or moreembodiments that may be used to incorporate this function may have anadditional bit latched that must be latched in all forms of theinstruction in order to include the protection provided by a CPU of thisarchitecture.

Another function provided hereunder is the ability to set a DP bit of aresult if any operand 402A-N in machine instructions 400A-N has a DP bit404A-N set (whether from a register or memory reference) as shown inFIG. 10. Specifically, in step TI, it is determined whether a userregister is loaded (from a system register). If not, the process maycontinue. If so, a corresponding instruction is executed in phases instep T2 to yield strings 400A-N that include source operands 402A-N andDP bits 404A-N. The DP bits 404A-N are then “ORed” together via OR gate406 to produce a DP bit 412 of a result 410. AS further shown, anarithmetic operation 408 may be performed based on operands 402A-N toyield result 410.

Another function provided hereunder is the ability to signal a dataprotection exception (DPE) as shown in FIG. 11. Specifically, a DPE maybe triggered if protected data is attempted to be: read into a register,stored from a register, used from an operand from memory, or stored to aresult in memory containing a different physical page key signature thanthe signature of the virtual page key of the current context within theassociated activation, process or thread. This process starts with theoperand's virtual address and the type of operation (whether read orwrite) provided in step V1 being converted to a page and an offset instep V2. A lookup is performed in step V3 within a physical pageprotection table (or physical page table in some embodiments), DP bitsand WP bits are extracted in step V4, and a protection bit array indexis extracted in step V5. As further shown, in step V6, a virtual pagekey register will be accessed and a physical page key/write allowedphysical page key (PPK/WPPK) signature will be calculated in step V7 asfurther shown, a series of AND gates 500A-C will be utilized to performvarious AND operations as shown (e.g., in conjunction with a read/write(R/W) operation in step V8. In addition, an output of AND gate 500C issubjected to a gate operation via operator 504 with the output of theR/W operation of step V8 so that a memory operation may be performed instep V9. Further yet, outputs of AND gates 500A-B are subjected to an“AND” operation via AND gate 500C as well as a “NAND” operation via NANDgate 502, which then signals a DPE in step V10.

In at least one embodiment of FIG. 11, a separate WPPK exists that wouldallow some processes to access the page in both read and write modes forcertain protected memory granules, whereas others use just a single pagePPK for controlled access for both DP as well as for WP functions. Asdescribed above, a virtual page number (VPN) and virtual page offset(VPO) are extracted from the operand virtual address. In one embodiment,the VPN may be used to find the virtual page number in the virtual pagetable (VPT) of the process, from which the physical page table entry(PPTE) is obtained to find the physical page protection table entry(PPPTE). In another embodiment, a reverse-lookup of the physical pagetable entry or physical page protection table entry may be performed.Additionally, a protection look-aside buffer may be used to reduce theamount of time needed to perform lookups (see US extended memoryprotection patent). In a PLB environment, the PLB would need to storethe DP and WP arrays as well as the PPK and WPPK data.

Once the PPPTE has been retrieved, the PPK or WPPK signature may becompared with the signature of the PPPTE's, PPK or WPPK (PPK for read,WPPK for write unless a single register is used for both). In anillustrative embodiment, a holding register may pre-calculate the PPKand WPPK signatures when the VPK or WVPK register is stored to. Thisincreases performance. Next, the DP and WP bits may be extracted andlatched from the PPPTE or PPTE by first selecting the portion of theoffset into the page that describes a protected granule of memory, andusing that section as an index into the DP and WP bit arrays of thePPPTE. The DP and WP bits are then compared with the output of the PPKor WPPK signature compare to determine if an operation of any kind tothis granule of memory is allowed. If the operation is not allowed, aData Protection Exception (DPE) is set to be signaled. If the operationis to be allowed, the memory operation is allowed to continue.

Another function provided is the ability to signal an illegal operationexception if an attempt is made in the wrong state to load the value ofthe virtual page key register (See FIG. 7). During instruction decode,the CPU state register is compared to determine if the CPU is in asecured state to allow the load of the VPK register.

I/O Architecture:

I/O architectures today provide a mechanism to place data in a certainmemory region and perform the I/O operation through either a directmemory access (DMA) mechanism or through a memory mapped I/O (MMI/O)architecture. In both of these architectures, a region of memory isdefined in which the data to be performed either exists or is to beinput. With DMA, a DMA device is programmed and subsequently triggeredto perform the I/O and indicates its completion through an interrupt. AnMM I/O operation is performed through access to an area of physicalmemory (by address) for which no physical memory exists allowing the I/Odevice to be selected when that memory address range is targeted for anoperation.

In either case, both DMA and MMI/O I/O architectures do not have anytype of defined data protection mechanism, and, in fact, such amechanism would increase the size of data, or conflict with variousstandards already in place. To compensate for this potentialcomplication, the following architectural definitions may be provided toallow I/O operations to take place successfully on protected memory. Thesimple definition of such a system is that:

-   -   A. For an I/O write operation, memory containing the source to        be transmitted to the I/O device would ignore the DP and WP        bits. This allows the write operation to complete without        knowledge of the operation.    -   B. For an I/O read operation, memory to which the I/O operation        would complete would need to be pre-masked by the operating        system to ensure that data protection would exist during the I/O        operation itself. This would need to include both the setting of        the appropriate PPK for the pages of memory as well as the DP        bits, and if the embodiment includes it, the WP bits, so that        when the block of memory is returned to the calling program. The        memory would be both protected and readable, and if some is not        writable, then the WP bits would be set as well.

Referring now to FIG. 12, a method flow diagram according to anembodiment of the present invention is shown (e.g., as enabled by engine50 of FIG. 2). As depicted, in step W1, a set of pages of data isidentified in computer storage. In step W2, a physical key is generatedfor each page of the set of pages, the physical key being stored in atleast one table. In step W3, a virtual key is generated based on eachphysical key, the virtual key identifying at least one processauthorized to use the data, and the virtual key being stored in at leastone register. In step W4, each page of the set of pages is protectedwith a respective physical key and corresponding virtual key. In stepW5, a data protection bit is set to a particular setting (e.g.,“protective”) to indicate a protective status of the set of pages ofdata.

While shown and described herein as a data security solution, it isunderstood that the invention further provides various alternativeembodiments. For example, in one embodiment, the invention provides acomputer-readable/useable medium that includes computer program code toenable a computer infrastructure to provide data security as discussedherein. To this extent, the computer-readable/useable medium includesprogram code that implements each of the various processes of theinvention. It is understood that the terms computer-readable medium orcomputer-useable medium comprise one or more of any type of physicalembodiment of the program code. In particular, thecomputer-readable/useable medium can comprise program code embodied onone or more portable storage articles of manufacture (e.g., a compactdisc, a magnetic disk, a tape, etc.), on one or more data storageportions of a computing device, such as memory 28 (FIG. 1) and/orstorage system 34 (FIG. 1) (e.g., a fixed disk, a read-only memory, arandom access memory, a cache memory, etc.).

In another embodiment, the invention provides a method that performs theprocess of the invention on a subscription, advertising, and/or feebasis. That is, a service provider, such as a Solution Integrator, couldoffer to provide data security functionality. In this case, the serviceprovider can create, maintain, support, etc., a computer infrastructure,such as computer system 12 (FIG. 1) that performs the processes of theinvention for one or more consumers. In return, the service provider canreceive payment from the consumer(s) under a subscription and/or feeagreement and/or the service provider can receive payment from the saleof advertising content to one or more third parties.

In still another embodiment, the invention provides acomputer-implemented method for data security. In this case, a computerinfrastructure, such as computer system 12 (FIG. 1), can be provided andone or more systems for performing the processes of the invention can beobtained (e.g., created, purchased, used, modified, etc.) and deployedto the computer infrastructure. To this extent, the deployment of asystem can comprise one or more of: (1) installing program code on acomputing device, such as computer system 12 (FIG. 1), from acomputer-readable medium; (2) adding one or more computing devices tothe computer infrastructure; and (3) incorporating and/or modifying oneor more existing systems of the computer infrastructure to enable thecomputer infrastructure to perform the processes of the invention.

As used herein, it is understood that the terms “program code” and“computer program code” are synonymous and mean any expression, in anylanguage, code, or notation, of a set of instructions intended to causea computing device having an information processing capability toperform a particular function either directly or after either or both ofthe following: (a) conversion to another language, code, or notation;and/or (b) reproduction in a different material form. To this extent,program code can be embodied as one or more of: an application/softwareprogram, component software/a library of functions, an operating system,a basic device system/driver for a particular computing device, and thelike.

A data processing system suitable for storing and/or executing programcode can be provided hereunder and can include at least one processorcommunicatively coupled, directly or indirectly, to memory elementsthrough a system bus. The memory elements can include, but are notlimited to, local memory employed during actual execution of the programcode, bulk storage, and cache memories that provide temporary storage ofat least some program code in order to reduce the number of times codemust be retrieved from bulk storage during execution. Input/outputand/or other external devices (including, but not limited to, keyboards,displays, pointing devices, etc.) can be coupled to the system eitherdirectly or through intervening device controllers.

Network adapters also may be coupled to the system to enable the dataprocessing system to become coupled to other data processing systems,remote printers, storage devices, and/or the like, through anycombination of intervening private or public networks. Illustrativenetwork adapters include, but are not limited to, modems, cable modems,and Ethernet cards.

The foregoing description of various aspects of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed and, obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to aperson skilled in the art are intended to be included within the scopeof the invention as defined by the accompanying claims.

What is claimed is:
 1. A computer-implemented method for managing datasecurity, comprising: identifying a set of pages of data in computerstorage associated with a computer system; generating a physical key foreach page of the set of pages, the physical key being stored separatelyfrom a physical page number in at least one table, the at least onetable located within a kernel of an operating system of the computersystem; generating a physical key signature corresponding to eachphysical key, wherein the physical key signature is smaller than thephysical key; generating a virtual key based on each physical key, thevirtual key identifying at least one process authorized to use the data,generating a virtual page key signature corresponding to each virtualkey, and the virtual key signature being stored in a virtual page keyregister, the virtual page key register comprising part of a centralprocessing unit of the computer system, and wherein the virtual page keyregister is accessible in a system state by the kernel of the operatingsystem only; protecting each page of the set of pages with a respectivephysical key and corresponding virtual key; setting a data protectionbit to a particular setting to indicate a protective status of the setof pages of data; and signaling a data protection exception in responseto storing the virtual key in the virtual page key register while thecentral processing unit is in a non-system state.
 2. Thecomputer-implemented method of claim 1, further comprising: receiving arequest to access the data for a particular process; determining if thedata protection bit is set to the particular setting; in response todetermining that the data protection bit is set to the particularsetting, identifying, based on the at least one table and the virtualpage key register, at least one physical key and at least one virtualkey that corresponds to the data and the particular process; determiningif the at least one physical key and the at least one virtual key matcha physical key and a virtual key associated with the request; andmaking, based upon the determining, an authentication extermination forthe requested access to the data.
 3. The computer-implemented method ofclaim 2, further comprising signaling a data protection exception if anyone of the at least one physical key and at least one virtual keymismatch the physical key and the virtual key associated with therequest.
 4. The computer-implemented method of claim 1, furthercomprising clearing a set of user registers whose corresponding dataprotection bits are engaged in response to a virtual page key registerbeing loaded in a system state.
 5. The computer-implemented method ofclaim 1, wherein the physical key is generated for a particular page inresponse to creation of at least one of: a new activation thatreferences the particular page or a new process that references theparticular page.
 6. The computer-implemented method of claim 1, furthercomprising transferring the data protection bit between a set of userregisters during at least one of a load operation and an arithmeticoperation.
 7. The computer-implemented method of claim 1, furthercomprising setting a data protection bit associated with a dataprocessing result based on a data protection bit associated with anoperand of a machine instruction.
 8. A system for managing datasecurity, comprising: a bus; a processor coupled to the bus; and amemory medium coupled to the bus, the memory medium comprisinginstructions to: identify a set of pages of data in computer storageassociated with a computer system; generate a physical key for each pageof the set of pages, the physical key being stored separately from aphysical page number in at least one table, the at least one tablelocated within a kernel of an operating system of the computer system;generate a physical key signature corresponding to each physical key,wherein the physical key signature is smaller than the physical key;generate a virtual key based on each physical key, the virtual keyidentifying at least one process authorized to use the data, andgenerate a virtual page key signature corresponding to each virtual key,and the virtual key signature being stored in a virtual page keyregister, the a virtual page key register comprising part of a centralprocessing unit of the computer system, and wherein the virtual page keyregister is accessible in a system state by the kernel of the operatingsystem only; protect each page of the set of pages with a respectivephysical key and corresponding virtual key; set a data protection bit toa particular setting to indicate a protective status of the set of pagesof data; and signal a data protection exception in response to storingthe virtual key in the virtual page key register while the centralprocessing unit is in a non-system state.
 9. The system of claim 8, thememory medium further comprising instructions to: receive a request toaccess the data for a particular process; determine if the dataprotection bit is set to the particular setting; in response todetermining that the data protection bit is set to the particularsetting, identify, based on the at least one table and the a virtualpage key register, at least one physical key and at least one virtualkey that corresponds to the data and the particular process; determineif the at least one physical key and the at least one virtual key matcha physical key and a virtual key associated with the request; and make,based upon the determining, an authentication extermination for therequested access to the data.
 10. The system of claim 9, the memorymedium further comprising instructions to signal a data protectionexception if any one of the at least one physical key and at least onevirtual key mismatch the physical key and the virtual key associatedwith the request.
 11. The system of claim 8, the memory medium furthercomprising instructions to clear a set of user registers whosecorresponding data protection bits are engaged in response to a virtualpage key register being loaded in a system state.
 12. The system ofclaim 8, wherein the physical key is generated for a particular page inresponse to creation of at least one of: a new activation thatreferences the particular page or a new process that references theparticular page.
 13. The system of claim 8, the memory medium furthercomprising instructions to transfer the data protection bit between aset of user registers during at least one of a load operation and anarithmetic operation.
 14. The system of claim 8, the memory mediumfurther comprising instructions to set a data protection bit associatedwith a data processing result based on a data protection bit associatedwith an operand of a machine instruction.
 15. A computer program productfor managing data security, the computer program product comprising acomputer readable hardware storage device, and program instructionsstored on the computer readable storage media, to: identify a set ofpages of data in computer storage associated with a computer system;generate a physical key for each page of the set of pages, the physicalkey being stored separately from a physical page number in at least onetable, the at least one table located within a kernel of an operatingsystem of the computer system; generate a physical key signaturecorresponding to each physical key, wherein the physical key signatureis smaller than the physical key; generate a virtual key based on eachphysical key, the virtual key identifying at least one processauthorized to use the data, generate a virtual page key signaturecorresponding to each virtual key, and the virtual key signature beingstored in a virtual page key register, the virtual page key registercomprising part of a central processing unit of the computer system, andwherein the virtual page key register is accessible in a system state bythe kernel of the operating system only; protect each page of the set ofpages with a respective physical key and corresponding virtual key; seta data protection bit to a particular setting to indicate a protectivestatus of the set of pages of data; and signal a data protectionexception in response to storing the virtual key in the virtual page keyregister while the central processing unit is in a non-system state. 16.The computer program product of claim 15, further comprising programinstructions stored on the computer readable storage media to: receive arequest to access the data for a particular process; determine if thedata projection bit is set to the particular setting; in response todetermining that the data projection bit is set to the particularsetting, identify, based on protection the at least one table and thevirtual page key register, at least one physical key and at least onevirtual key that corresponds to the data and the particular process;determine if the at least one physical key and the at least one virtualkey match a physical key and a virtual key associated with the request;and make, based upon the determining, an authentication exterminationfor the requested access to the data.
 17. The computer program productof claim 16, further comprising program instructions stored on thecomputer readable hardware storage device to signal a data protectionexception if any one of the at least one physical key and at least onevirtual key mismatch the physical key and the virtual key associatedwith the request.
 18. The computer program product of claim 15, furthercomprising program instructions stored on the computer readable hardwarestorage device to clear a set of user registers whose corresponding dataprotection bits are engaged in response to a virtual page key registerbeing loaded in a system state.
 19. The computer program product ofclaim 15, wherein the physical key is generated for a particular page inresponse to creation of at least one of: a new activation thatreferences the particular page or a new process that references theparticular page.
 20. The computer program product of claim 15, furthercomprising program instructions stored on the computer readable hardwarestorage device to transfer the data protection bit between a set of userregisters during at least one of a load operation and an arithmeticoperation.
 21. The computer program product of claim 15, furthercomprising program instructions stored on the computer readable hardwarestorage device to set a data protection bit associated with a dataprocessing result based on a data protection bit associated with anoperand of a machine instruction.
 22. A method for deploying a systemfor managing data security, comprising: providing a computerinfrastructure being operable to: identify a set of pages of data incomputer storage associated with a computer system; generate a physicalkey for each page of the set of pages, the physical key being storedseparately from a physical page number in at least one table, the atleast one table located within a kernel of an operating system of thecomputer system; generate a physical key signature corresponding to eachphysical key, wherein the physical key signature is smaller than thephysical key; generate a virtual key based on each physical key, thevirtual key identifying at least one process authorized to use the data,generate a virtual page key signature corresponding to each virtual key,and the virtual key signature being stored in a virtual page keyregister, the virtual page key register comprising part of a centralprocessing unit of the computer system; protect each page of the set ofpages with a respective physical key and corresponding virtual key; seta data protection bit to a particular setting to indicate a protectivestatus of the set of pages of data; and signal a data protectionexception in response to storing the virtual key in the virtual page keyregister while the central processing unit is in a non-system state.